Mini-caliber firearm for launching hypervelocity projectiles

ABSTRACT

In order to provide an accurate, low-mass, highly effective personal weapon, a firearm has been designed. The projectile mass is such that the ratio thereof to the firearm mass will provide a weapon of extremely light weight and yet heavy enough to be virtually unaffected by the recoil forces generated during the firing thereof, but sufficient for excellent lethality. The components of the weapon are limited to a hand-held receiver, a barrel slidably disposed in the forward end of the receiver, a coiled tension spring for coupling the barrel to the receiver, a sear for releasably retaining the barrel in a forward cocked position against the bias of the spring, and an optional safety for blocking release of the sear. Upon release by the sear, the barrel is biased rearwardly to bring the cartridge chambered therein into firing contact with a fixed striker in the receiver.

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Hudson July 23, 1974 MINI-CALIBER FIREARM FOR Primary Examiner-Samuel Feinberg LAUNCHING HYPERVELOCITY Assistant ExaminerC. T. Jordan PROJECTILES Attorney, Agent, or Firm-Edward J. Kelly Herbert Ber] [75] Inventor: Colin M. Hudson, Moline, I11.

[73] Assignee: The United States of America as represented by the Secretary of the [57] ABSTRACT Army, Washington, In order to provide an accurate, low-mass, highly cf- [22] Filed: 14, 1973 fective personal weapon, a firearm has been designed. The projectile mass is such that the ratio thereof to PP NOJ 388,310 the firearm mass will provide a weapon of extremely light weight and yet heavy enough to be virtually unaf- [52] US. Cl. 42/1 J fected by the recoil forces generated during the firing 51 Int. Cl. F41c 9/02 themfi but Sufficisnt for excellent lethality The [58]. Field of Search n 42 J 1 G 1 H, 1 Z, ponents of the weapon are limited to a hand-held re- 42/10; 89/161 ceiver, a barrel slidably disposed in the forward end of the receiver, a coiled tension spring for coupling the [56] References Cited barrel to the receiver, a sear for releasably retaining the barrel in a forward cocked position against the UNITED STATES PATENTS bias of the spring, and an optional safety for blocking 1,681,172 8/1928 Cocho 42/1 J release of the sear Upon release by the Sear the 5 831 122 gbbottm 42 J rel is biased rearwardly to bring the cartridge chamuncan bered therein into firing contact with a fixed striker in FOREIGN PATENTS OR APPLICATIONS the receiver.

154,068 4/1956 Sweden 42/1 Z 7 Claims, 5 Drawing Figures MINI-CALIBER FIREARM FOR LAUNCHING HYPERVELOCITY PROJECTILES BACKGROUND OF THE INVENTION This invention relates to small arms of mini-caliber size, i.e., less than caliber .22, and is more particularly directed to a self-defense type of hand-held firearm capable of firing projectiles at hypervelocity speeds.

While small caliber pistols are generally regarded as best-suited for self-defense purposes, the effectiveness thereof in emergency situations, such as the hijacking of an aircraft in flight, is substantially diminished by the relatively time-consuming effort required to shift from a concealed or stowed position to an aimed position, release the safety, and place the trigger finger in a ready-to-fire position. In addition, the heavy recoil often causes the user to miss a target. Attempts to improve the ease with which a conventional pistol can be brought to bear against a given target in a rapid and unobtrusive manner have heretofore been limited to reducing the size and caliber thereof. However, it has been found that conventional pistols of less than caliber .22 in size do not provide the accuracy and striking power required to incapacitate an assailant under close and crowded conditions. Experience has also shown that where the'components in the cooking and firing mechanisms of conventional pistols are significantly reduced in size, the functional simplicity and reliability thereof are adversely affected.

SUMMARY OF THE INVENTION It has been discovered that the foregoing disadvantages encountered in many pistols which have been reduced to mini-caliber size can be successfully overcome by a weapon which fires an appropriate projectile of very low mass (say 1 to 3 grains) at extremely high velocity. The design of such a weapon uses a structure wherein the firing pin or striker is integrally formed within the interior of an elongated oval housing which is, in turn, slidably fitted onto the breech end of the barrel and flexibly coupled thereto by a coiled tension spring. The rear end of the spring is threaded directly into the interior of the housing in surrounding relation to the striker while the forward end of the spring is similarly threaded onto the breech end of the barrel. When either the striker housing or the barrel is manipulated to tension the spring, the forward end of a sear pivoted in the housing drops into a notch formed in the upper periphery of the barrel to retain the latter in a cocked position. If desired, the housing may be provided with a safety which can be manually rotated into position to block the firing release of the sear. When the sear is pivoted out of the sear notch in the barrel, the extension spring will retract the latter to bring the chambered round in the breech end thereof into firing impact with the striker in the housing. The striker housing fits over the breech end of the barrel to serve as a guide for the reciprocation thereof. A plug threaded into the breech end of the barrel chamber following the loading of a round therein serves as a fixed breechblock. The round is designed to provide sufficient power to propel a spherical projectile or cylindrical flechette of minicaliber size through the corresponding bore in the barrel at a velocity which will incapacitate an assailant regardless of where he may be hit. Furthermore, the streamlined exteriors of the striker housing and the barrel provide a relatively unobstructed and symmetrical configuration which facilitates the handling involved in transferring the firearm from a concealed or stowed position to a ready-to-fire position thereby improving the ability of the user to fire rapidly and accurately against a moving target.

It is, therefore, an object of this invention to provide a hand-held firearm, less than caliber .22 in size, capable of firing projectiles with an accuracy and lethality substantially equivalent to or greater than that of a conventional pistol of considerably larger caliber.

A further object of the present invention is to provide a personal defense weapon system, as aforesaid, wherein the size, configuration andweight is specifically designed to facilitate the handling thereof involved in shifting from a concealed or stowed position to an aimed, ready-to-fire status.

Another object of this invention lies in the provision of a reliable and effective firearm, as aforesaid, wherein the firing mechanism consists of a fixed striker which does not require any headspace control.

Still another object of this invention is to provide a small compact firearm for launching projectiles of mini-caliber size at hypervelocity speeds with no discernible recoil movement.

A further object of this invention is the provision of a throwaway self-defense firearm wherein the mass thereof and that of the projectiles are specifically selected to provide a muzzle velocity in excess of 5,000 feet per second and yet avoid any discernible recoil movement thereof during firing.

An additional object of this invention is to provide a simple and inexpensive preloaded firearm, as aforesaid, wherein the firing mechanism therefor is almost completely sealed against moisture, dust, and other detrimental elements of the environment.

BRIEF DESCRIPTION OF THE DRAWING The exact nature of the invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawing, wherein:

FIG. 1 is a perspective view of the firearm in the cocked position thereof with the muzzle end of the barrel broken away to show the rear end of the muzzle cap;

FIG. 2 is an enlarged side view partly in section showing the details of the firing and cocking mechanism in the cocked position thereof;

FIG. 3 is a section taken along line 33 in FIG. 2 to show the manner in which the safety prevents manual actuation of the sear;

FIG. 4 is a view similar to that of FIG. 2 but showing the position of the parts following the firing release of the sear and the movement of the barrel to the tired position; and

FIG. 5 is a section taken along line 55 of FIG. 4 showing the manner in which the sear is mounted to the housing. 1

DESCRIPTION OF A PREFERRED EMBODIMENT As shown in the drawing, wherein similar reference characters are employed to designate corresponding parts throughout, the basic components of the firearm of the present invention are a firing member or receiver 12 housing an integral striker 14, a barrel l6 slidably coupled to the interior of receiver 12, and a sear 18 for releasably retaining barrel 16 in a cocked position relative to striker 14.

Receiver 12 is a elongated generally oval-shaped member having a forwardly opening hollow interior 20 terminating in a closed rear end and of sufficient diameter to slidably receive the breech end of barrel 16. Striker 14 is preferably integrally joined to the rear end wall within receiver interior 20 and extends forwardly therefrom to terminate in a firing tip 22 of reduced diameter. The junction between firing tip 22 and the remainder of striker 14 provides an annular shoulder 24 for halting the rearward movement of barrel 16.

In order to permit the launching of projectiles at hypervelocity speeds, barrel 16 is formed with a smooth bore of mini-caliber size, i.e., between 0.125 and 0.220 inches in diameter and of sufficient elongation to provide a length/diameter ratio of about 50 to l. The breech end of the barrel bore is counterbored to about twice the diameter of the bore, as i dicated at 26, and is also provided with a circumf rential recess 28 adjacent the forward face 27 f counterbore 26 to accommodate the enlarged im at the base of a stub cartridge case 30. A sabot 32 of molded plastic is suitably pressfitted into the outh of case 30 and a spherical projectile 34 betw en 1-3 grains in weight is completely embedded in sabot 32. Greater target penetration may be obta jectile, i.e., arT arr ow-sha ped needle' with a plurality or fins at the rear end thereof. For best results in accuracy and striking power, such flechettes are designed to provide a length/diameter ratio of between to l and to l and are preferably fabricated of a relatively dense material such as tungsten alloy, for example. An impact plug 36 is threadably inserted into counterbore 26 in position to abut the base of cartridge case and is provided with a central hole 38 therethrough for passage of the firing tip 22 of striker l4. Inasmuch as impact plug 36 is slightly smaller in length than firing tip 22, the latter will have completed the required firing impact with the primer in cartridge case 30 by the time the rearward travel of barrel 16 is halted by annular shoulder 24 on striker 14.

The breech end of barrel 16 is also provided with a reduced diameter exterior portion 40 and a threaded section 42 forwardly adjacent thereto. One end of a coiled tension spring 44 is threaded onto section 42 of barrel 16 and, although the diameter of the coils is slightly less than the root diameter of the threads on barrel section 42, the pitch of such coils provides sufficient flexibility thereto to readily conform to the slight expansion imparted thereto during assembly onto barrel 16. However, the binding pressure exerted on barrel section 42 by the expanded coils effectively resists any tendency thereof toward rotation in the direction of disassembly.

The rear end portion of central opening 20 is also threaded, as indicated at 46, to the same pitch and longitudinal extent as barrel section 42. Once assembly of spring 44 onto barrel 16 is completed, both components are inserted into central opening 20 in receiver 12 and barrel l6 rotated until spring 44 is threaded into engagement with all of threads 46. As in the case of the coils at the forward end of spring 44, the coils at the rearward end thereof are readily threaded into central opening 20 but thereafter resist any rotation thereof in the opposite direction. Thus, once spring 44 is threaded into receiver opening 12 and onto the breech end of barrel 16, the distance to which firing tip 22 is permitted to protrude beyond impact plug 36 will not be altered despite any rotation of barrel 16 relative to receiver 12. The portion of spring 44 between the engaged ends thereof is free to be extended in response to any movement of the breech face of barrel 16 away from striker 14.

The retention of barrel 16 in a cocked, ready-to-fire position is accomplished by sear 18 which is pivoted to the exterior of receiver 12 and is preferably formed of flat spring stock curved to provide a longitudinally bowed first class lever. Sear 18 is provided with a depending mounting lug which fits into a suitable recess 52 in the exterior periphery of receiver 12 and is pivotally retained in place by a transverse pin 54, as best shown in FIG. 5. The forward end of sear 18 terminates in a depending nose 56 of sufficient length to pass through a suitable hole 58 in receiver 12 and enter into a rectangular notch 60 in the exterior periphery of barrel 16. Rearwardly of lug 50, sear 18 is of reduced cross-section, as indicated at 48, and terminates in a reverse curl 62 at the rear end thereof arranged to resiliently press against the exterior periphery of receiver 12 as a result of the differing curvatures of sear 18 and receiver 12. The spring action thus imparted to sear 18 tends to resist pivotal disengagement of nose 56 from sear notch 60 as barrel 16 is being longitudinally displaced forwardly in receiver 12. Sear notch 60 is so located in barrel 16 that upon entry therein of sear nose 56, the breech face of barrel 16 will be positioned, as best shown in FIG. 2, slightly forward of firing tip 22 on striker 14.

The exterior of receiver 12 is circumferentially recessed, as indicated at 63 in FIGS. 2 and 4, to rotatably seat an annular safety 64 provided with a pair of spaced apart blocking lugs 66 projecting outwardly therefrom to a slightly greater distance than the space between the underside of sear portion 48 and the exterior periphery of receiver 12. As safety 64 is rotated by the pressure of the thumb or index finger of the firearm operator on one of blocks 66, the other block will be forced beneath sear 48 into releasable retention therewith. To this end, the opposite edges of sear 18 are of rolled construction, as best shown at 68 in FIG. 3, to prevent accidental rotation of safety 64 while the firearm is in a concealed or stowed position.

The muzzle end of barrel 16 is protected against the entry of moisture, dirt, and other environmental material which might, in time, lead to deterioration of the cartridge or of spring 44. Such protection is afforded by a simple disposable muzzle cap 70 of a molded plastic material provided with a protruding stem 72 dimensioned to be press-fitted into the bore of barrel 16 at the muzzle end thereof. When the firearm is discharged, the resulting gases will compress the air in the bore of barrel l6 and thereby produce sufficient pressure to blow muzzle cap 70 off of barrel 16 prior to the exit of projectile 34 therefrom.

The loading of ammunition in the firearm is, of course, accomplished prior to the assembly of impact plug 36 into barrel l6. Thereafter, plug 36 is threaded into counterbore 26 until halted by abutment with, as in this embodiment, cartridge case 30. Tension spring 44 is then assembled into the threaded rear end portion 46 of receiver 12. The breech end of barrel 16 is then inserted into opening 20 in receiver 12, and the barrel is then rotated to engage threaded section 42 with the forward end of spring 44, care being taken to simultaneously extend spring 44 sufficiently to avoid contact between the cartridge primer and striker 14. Finally, barrel 16 and receiver 12 are pulled apart until sear nose 56 engages in notch 60 in barrel 16 to retain the latter in the cocked position thereof. In view of the rather extensive manipulation required to accomplish the foregoing loading and cocking procedures, the use of the firearm for more than one firing is not considered practical and consequently the design and fabrication of parts are oriented toward treating the firearm as a throwaway item to be discarded after firing. In other words, the mini-caliber firearm of the present invention is like a self-contained unit such as a hand grenade intended for disposal immediately after use. In the event circumstances require the firing of more than one cartridge, this may be conveniently accomplished by the employment of several separate firearms. The small size and low weight of each firearm would readily permit the concealment or stowage of more than one unit on the person of the operator. However, if still more firepower should be required, the barrel could be enlarged to incorporate a plurality of bores or individual tubes radially disposed about a common central axis in position to chamber a corresponding number of preloaded cartridges. Firing of these cartridges in sequence could be readily accomplished by 'a simple semiautomatic striker mechanism or by a suitable electric ignition system incorporating a conventional stepping switch.

In order to fire the single shot version shown in the drawing, the operator need only to remove the firearm from its concealed or stowed position, grasp receiver 12 in the palm of one hand, and raise the firearm to an aiming position while simultaneously using the thumb or index finger to rotate safety 64 out of engagement with sear l8. Thereafter, pressing downward on the reduced cross-section portion 48 of sear 18, will lift sear nose 56 out of notch 60 in barrel l6 and permit the extended central portion of spring 44 to impart a rapid rearward movement to barrel 16. As threaded plug 36 impacts against annular shoulder 24 on striker l4, firing tip 22 thereon has passed through hole 38 to strike the primer in cartridge case 30 and initiate firing. Thus, the impact of the moving barrel 16 and the setback of the fired cartridge are both absorbed by the much greater mass of receiver 12. In addition, the recoil forces produced by the acceleration imparted to sabot 32 and projectile 34 imbedded therein are transferred through barrel 16 to receiver 12. Since the combined weight of sabot 32 and projectile 34 is on the order of 3 grains while the weight of the entire firearm can be controlled to within 4 ounces, the nearly 600 to 1 ratio of firearm to projectile mass results in the virtual absence of any recoil movement thereby permitting the attainment of highly accurate fire. Furthermore, inasmuch as the projectile possesses a unique combination of high density and minimum cross-section, the muzzle velocity thereof will exceed 5,000 feet per second which, at the relatively close ranges for which the firearm is designed, will produce a corresponding striking velocity of over 4,000 feet per second thereby insuring a relatively high degree of lethality against a human or other animal target.

Thus, there is here provided a remarkably lightweight firearm which can be readily drawn from a concealed or stowed position and fired with a high degree of accuracy and lethality. The firing mechanism therefor is of such simplicity that no headspace control is required and yet provides positive firing once the safety has been released. The firearm is additionally unique in that it is a preassembled throw-away item essentially devoid of all openings which will permit the entry of undesirable moisture, dirt, or other foreign material affecting the ability of the ammunition and firing components to function in a reliable manner even after a relatively long period of non-use. Although the present invention is shown and described as utilizing a cased round of ammunition, it will be recognized by persons skilled in the art that other forms of ammunition are readily adaptable to the firearm. For example, caseless ammunition, or ammunition comprising separate propellant and projectile components may be utilized.

The foregoing disclosure and description of the invention is illustrative only. Various changes may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. A hand-held firearm for firing a mini-caliber car- .tridge comprising,

a hollow receiver having a forwardly projecting striker integrally formed within the interior thereof,

a barrel slidably disposed in said receiver to project forwardly from one end thereof, said barrel having a cartridge chamber in the breech end thereof,

a tension spring having one end threadably engaged in said receiver and having the opposite end thereof similarly engaged with the breech end of said barrel whereby the portion therebetween is freely disposed to perform the spring function, and

a sear pivoted on said receiver for releasably retaining said barrel forwardly of said striker against the resilient bias of said spring whereby the release of said barrel by said sear allows said spring to retract said barrel into operative firing contact with said striker.

2. The firearm as defined in claim 1 including safety means rotatably and releasably disposed on the exterior surface of said receiver for retaining said sear in an operative position.

3. A hand-held firearm for firing a mini-caliber projectile comprising,

a receiver having a hollow interior terminating in a forward open end and in a closed rear end,

a striker extending forwardly from said rear end within said receiver and terminating in a firing tip of reduced diameter,

a barrel having an impact plug threaded in the breech end thereof and an ammunition chamber forwardly of said plug, said breech end being disposed within saidreceiver open end,

a tension spring having the rear end thereof secured within said receiver interior and extending forwardly in surrounding relation to said striker, the forward end of said spring being secured to the breech end of said barrel,

a sear pivotally mounted on the exterior of said receiver, and

releasable means on said sear disposed for engagement with said barrel in response to the bias of said spring thereby to retain said barrel in a cocked position preparatory to release for firing said projectile.

4. The firearm as defined in claim 3 wherein said impact plug is disposed in abutment with ammunition disposed in said barrel and is provided with a hole therethrough for the passage of said firing tip in response to rearward movement of said barrel relative to said receiver.

5. The firearm as defined in claim 3 wherein said receiver is provided with a hole disposed through a side wall thereof and communicating with said hollow interior, said barrel being provided with a notch in the exterior periphery disposed for alignment with said receiver hole in response to said barrel being manually actuated against the bias of said spring to a cocked position, and said sear having a depending portion at the forward end thereof engageable with said barrel notch thereby releasably retaining said barrel against the bias of said spring.

6. The firearm as defined in claim 3 and including a forwardly tapering cap having a rear face equal in diameter to said barrel and a rearwardly projecting stem releasably fitted into the muzzle end of said barrel to protect the bore thereof against the environment, said cap being releasable from said barrel in response to an increase in pressure in the barrel bore incident to firing ammunition in said firearm.

7. A hand-held, self-defense firearm for launching a mini-caliber projectile at hypervelocity speed comprising,

a receiver having a fixed striker therein,

a barrel slidably disposed in the forward end of said receiver and having a bore diameter of less than .22 caliber for chambering a cartridge containing a sabot with a projectile embedded therein,

a tension spring having one end engaged in said receiver and the opposite end thereof engaged with said barrel, and

sear means in said receiver for releasably retaining said barrel forwardly of said striker and against the bias of said tension spring whereby the cartridge is urged into firing contact with said striker upon the release of said barrel by said sear means, the ratio of projectile to firearm mass being selected to prevent any recoil movement thereof responsive to the firing of the cartridge and yet permit launching of the projectile at a muzzle velocity in excess of 5,000 feet per second. 

1. A hand-held firearm for firing a mini-caliber cartridge comprising, a hollow receiver having a forwardly projecting striker integRally formed within the interior thereof, a barrel slidably disposed in said receiver to project forwardly from one end thereof, said barrel having a cartridge chamber in the breech end thereof, a tension spring having one end threadably engaged in said receiver and having the opposite end thereof similarly engaged with the breech end of said barrel whereby the portion therebetween is freely disposed to perform the spring function, and a sear pivoted on said receiver for releasably retaining said barrel forwardly of said striker against the resilient bias of said spring whereby the release of said barrel by said sear allows said spring to retract said barrel into operative firing contact with said striker.
 2. The firearm as defined in claim 1 including safety means rotatably and releasably disposed on the exterior surface of said receiver for retaining said sear in an operative position.
 3. A hand-held firearm for firing a mini-caliber projectile comprising, a receiver having a hollow interior terminating in a forward open end and in a closed rear end, a striker extending forwardly from said rear end within said receiver and terminating in a firing tip of reduced diameter, a barrel having an impact plug threaded in the breech end thereof and an ammunition chamber forwardly of said plug, said breech end being disposed within said receiver open end, a tension spring having the rear end thereof secured within said receiver interior and extending forwardly in surrounding relation to said striker, the forward end of said spring being secured to the breech end of said barrel, a sear pivotally mounted on the exterior of said receiver, and releasable means on said sear disposed for engagement with said barrel in response to the bias of said spring thereby to retain said barrel in a cocked position preparatory to release for firing said projectile.
 4. The firearm as defined in claim 3 wherein said impact plug is disposed in abutment with ammunition disposed in said barrel and is provided with a hole therethrough for the passage of said firing tip in response to rearward movement of said barrel relative to said receiver.
 5. The firearm as defined in claim 3 wherein said receiver is provided with a hole disposed through a sidewall thereof and communicating with said hollow interior, said barrel being provided with a notch in the exterior periphery disposed for alignment with said receiver hole in response to said barrel being manually actuated against the bias of said spring to a cocked position, and said sear having a depending portion at the forward end thereof engageable with said barrel notch thereby releasably retaining said barrel against the bias of said spring.
 6. The firearm as defined in claim 3 and including a forwardly tapering cap having a rear face equal in diameter to said barrel and a rearwardly projecting stem releasably fitted into the muzzle end of said barrel to protect the bore thereof against the environment, said cap being releasable from said barrel in response to an increase in pressure in the barrel bore incident to firing ammunition in said firearm.
 7. A hand-held, self-defense firearm for launching a mini-caliber projectile at hypervelocity speed comprising, a receiver having a fixed striker therein, a barrel slidably disposed in the forward end of said receiver and having a bore diameter of less than .22 caliber for chambering a cartridge containing a sabot with a projectile embedded therein, a tension spring having one end engaged in said receiver and the opposite end thereof engaged with said barrel, and sear means in said receiver for releasably retaining said barrel forwardly of said striker and against the bias of said tension spring whereby the cartridge is urged into firing contact with said striker upon the release of said barrel by said sear means, the ratio of projectile to firearm mass being selected to prevent any recoil movement thereof responSive to the firing of the cartridge and yet permit launching of the projectile at a muzzle velocity in excess of 5,000 feet per second. 